encourages users to fail futures properly
clarified per marius
Use marius' suggested wording with small style cleanups
Merge branch 'master' into gdickinson/fail-futures-takeover
Small wording error
Adopt Marius' line-edit suggestions
Merge pull request #52 from gdickinson/gdickinson/fail-futures-takeover

Encourage use of Future.exception over throw for non-fatals.